Add basic CRT interaction routine from frame sync.

src/crt.c

@@ -0,0 +1,10 @@
+#include "crt.h"
+
+#include <stdint.h>
+
+void crt_waitNextFrame(void) {
+    void (*frame_sync_detection_routine)(void) = (void *)0xc75b;
+    __asm__("push af");
+    frame_sync_detection_routine();
+    __asm__("pop af");
+}

src/crt.h

@@ -0,0 +1,6 @@
+#ifndef CEDA_CRT_H
+#define CEDA_CRT_H
+
+void crt_waitNextFrame(void);
+
+#endif // CEDA_CRT_H